Outputs from first and second DC power supplies are controlled based on a first reactor current and a second reactor current. For controlling an output from a corresponding DC power supply, a relative maximum point and a relative minimum point as two inflection points are provided in a high current of the first and second reactor currents in one control cycle, by controlling on and off of switching elements. In a low current of the first and second reactor currents, inflection points more than in the high current are provided. Each of the inflection points on a side of the high current is provided at timing identical to the inflection point on a side of the low current.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A power supply system which controls a DC voltage between a first power line on a high voltage side and a second power line on a low voltage side, comprising: a first DC power supply; a second DC power supply; a power converter which carries out DC voltage conversion between the first and second DC power supplies and the first and second power lines; and a control device which controls an operation of the power converter, the power converter including a first semiconductor element electrically connected between the first power line and a first node, a first reactor electrically connected in series with the first DC power supply, between the first node and the second power line, a second semiconductor element electrically connected between the second power line and the first node, a second reactor electrically connected in series with the second DC power supply, between a second node and the first power line, a third semiconductor element electrically connected between the second node and the second power line, a fourth semiconductor element electrically connected between the first power line and the second node, and a fifth semiconductor element electrically connected between the first node and the second node, at least some of the first to fifth semiconductor elements each including a switching element which is configured to control formation and cut-off of a current path in response to a signal from the control device, each of a first reactor current which flows through the first reactor and a second reactor current which flows through the second reactor being controlled to have a plurality of inflection points in each control cycle as a result of control of on and off of the switching element in response to a control signal from the control device, the control device including a first switching control mode in which the control signal for the switching element is generated such that a first current greater in absolute value of the first and second reactor currents has first and second inflection points representing any one and the other of a relative maximum point and a relative minimum point, respectively, in each control cycle and a second current smaller in absolute value of the first and second reactor currents has third and fourth inflection points representing any one and the other of the relative maximum point and the relative minimum point, respectively, in addition to the first and second inflection points representing any one and the other of the relative maximum point and the relative minimum point, respectively, in each control cycle, and in the first switching control mode, the first inflection point of the first current and the first inflection point of the second current appearing at identical timing, and the second inflection point of the first current and the third inflection point of the second current appearing at identical timing.
2. The power supply system according to claim 1 , wherein in the first switching control mode, during a period in which both of the first and second DC power supplies perform a power running operation or a regeneration operation, any one and the other of the first inflection points of the first and second currents are the relative maximum point and the relative minimum point, respectively, and any one and the other of the second inflection point of the first current and the third inflection point of the second current are the relative maximum point and the relative minimum point, respectively.
3. The power supply system according to claim 2 , wherein the control device further has a second switching control mode in which the control signal for the switching element is generated such that each of the first and second reactor currents has first and second inflection points representing any one and the other of the relative maximum point and the relative minimum point, respectively, in each control cycle, and the control device generates the control signal for the switching element such that the first and second switching control modes are alternately applied.
4. The power supply system according to claim 1 , wherein the control device further has a second switching control mode in which the control signal for the switching element is generated such that each of the first and second reactor currents has first and second inflection points representing any one and the other of the relative maximum point and the relative minimum point, respectively, in each control cycle, and the control device generates the control signal for the switching element such that the first and second switching control modes are alternately applied.
5. The power supply system according to claim 1 , wherein the control device generates the control signal for the switching element such that the first and second inflection points appear in the first reactor current in accordance with comparison between a first output duty ratio with which an output from the first DC power supply is controlled and a first carrier wave having a voltage width corresponding to a maximum value of the first output duty ratio and the first and second inflection points appear in the first reactor current in accordance with comparison between a second output duty ratio with which an output from the second DC power supply is controlled and a second carrier wave having a voltage width corresponding to a maximum value of the second output duty ratio.
6. The power supply system according to claim 1 , wherein each of the first to fourth semiconductor elements includes the switching element for selectively forming an on state in which a current path is formed and an off state in which the current path is cut off, in response to the signal from the control device, and a diode connected in anti-parallel to the switching element, for forming a current path during forward biasing, and the fifth semiconductor element includes the switching element for controlling formation and cut-off of a current path between the first node and the second node.
7. The power supply system according to claim 1 , wherein each of the first to fourth semiconductor elements includes the switching element for selectively forming an on state in which a current path is formed and an off state in which the current path is cut off, in response to the signal from the control device, and a diode connected in anti-parallel to the switching element, for forming a current path during forward biasing, and the fifth semiconductor element includes the switching element for controlling formation and cut-off of a current path from the first node to the second node and the switching element for controlling formation and cut-off of a current path from the second node to the first node.
8. The power supply system according to claim 1 , wherein the switching element is provided in each of the second and fourth semiconductor elements, a diode connected to have a direction from the first node toward the first power line as a forward direction and a diode connected to have a direction from the second power line toward the second node as the forward direction are provided in the first and third semiconductor elements, respectively, and the switching element for controlling formation and cut-off of at least a current path from the first node to the second node is provided in the fifth semiconductor element.
9. The power supply system according to claim 8 , wherein the switching element connected in parallel with the diode is further provided in any one of the first and third semiconductor elements.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 31, 2016
November 20, 2018
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